README.md: Add section about SAM Broadcaster Smart Categories.

README.md

@@ -48,6 +48,7 @@ Both standalone Liquidsoap operation and integrated playout systems like AzuraCa
       - [`liq_cue_file` (`true`/`false`)](#liq_cue_file-truefalse)
       - [`liq_blankskip` (seconds; 0.0 to disable)](#liq_blankskip-seconds-00-to-disable)
       - [AzuraCast: `jingle_mode` (`"true"`)](#azuracast-jingle_mode-true)
+      - [SAM Broadcaster Smart Categories](#sam-broadcaster-smart-categories)
     - [Effect of `settings.autocue.cue_file.unify_loudness_correction` (`true`/`false`)](#effect-of-settingsautocuecue_fileunify_loudness_correction-truefalse)
       - [ReplayGain inserted](#replaygain-inserted)
       - [ReplayGain overriding `liq_amplify`](#replaygain-overriding-liq_amplify)
@@ -545,6 +546,14 @@ So if `autocue` sees this annotation (or tag in a file), it will automatically _
 
 Note this setting is superceded by `liq_blankskip`, the "ultimate blankskip switch". So if _both_ are there, the setting from `liq_blankskip` will "win".
 
+#### <a name="sam-broadcaster-smart-categories"></a>SAM Broadcaster Smart Categories <a href="#toc" class="goToc">⇧</a>
+
+This is a convenience feature for those who came from _SAM Broadcaster/SAM DJ_, or share a music library with SAM, and have used [SAM Broadcaster "Smart Categories"](https://support.spacial.com/hc/en-us/articles/229535987-SAM-Broadcaster-SAM-DJ-Using-Smart-Categories) to categorize their tracks. _Smart Categories_ are held in a `songtype` tag, whose contents is a single letter: `S` for normal songs, `I` for Station ID, `J` for Jingle, `N` for News, and so on.
+
+When detecting the `songtype` tag in a file, and it is _not_ `S` (Song), `autocue` will automatically _disable_ "blankskip" for this track.
+
+Note this setting is superceded by `liq_blankskip`, the "ultimate blankskip switch". So if _both_ are there, the setting from `liq_blankskip` will "win".
+
 ### <a name="effect-of-settingsautocuecue_fileunify_loudness_correction-truefalse"></a>Effect of `settings.autocue.cue_file.unify_loudness_correction` (`true`/`false`) <a href="#toc" class="goToc">⇧</a>
 
 Unify `replaygain_track_gain` and `liq_amplify`. If enabled, this will ensure both have the same value, with `replaygain_track_gain` taking precedence if we can see it. Allows scripts to amplify on either value, without getting loudness jumps.